Abraham martin



I 4 (No Model.)

, A. MARTIN.

METALLIG CARTRIDGE.

No. 408,917. Patented Aug. 13, 1889'.

z I 1 1 1 r r 1 [III UNITED STATES PATENT OFFICE.

ABRAHAM MARTIN, OF 177 ASTON LANE, WVITTON, NEAR BIRMINGHAM, COUNTY OF VVARYVIOK, ENGLAND.

METALLIC CARTRIDGE.

SPECIFICATION forming pait of Letters Patent No. 408,917, dated August 13, 1889.

Application filed December 4, 1888.

To all whom it may concern:

Be it known that I, ABRAHAM MARTIN, engineer, at present residing at 177 Aston Lane, Vitton, near Birmingham, in the county of Varwick, England, have invented new and useful Improvements in Metallic Cartridges, of which the following is a full, clear, and exact description.

This invention relates to the manufacture of metallic cartridges for small-arms and machine and other guns for which such cartridges are used. The cartridges are of that kind for which a solid drawn metal bottle-shaped cartridge-case especially adapted to be filled with a solid or compressed explosive charge is employed. Such solid charges are necessarily introduced atthe base end of the case, owing to the bottle-like form of the latter, and the joint between the part by which the base end is closed and the sides is liable to leakage under the expansive pressure of the gases.

Reference is to be had to the accompanying drawings, forming part of this specification, in which Figure 1 represents a longitudinal section of a bottle-shaped cartridge constructed according to my invention, and Fig. 2 shows the two parts of the case separately.

The same letters of reference serve for like parts in both figures.

My invention has for its object to afford all the necessary strength and perfect absence from leakage; and it consists of an inner solid drawn sheath or .case a at, having its cylindrical portion a and base a in one piece of metal and adapted to fit tightly within the open base end and cylindricalpartb of a solid drawn cartridge case. This inner case or sheath a a is of such length as to wholly contain the solid or compressed charge 0, which when thus ensheathed and introduced into the outer principal case b is surrounded circumferentially by a double metallic cartridgecase.

The inner sheath or case a a may be made of the same metal as is generally used for the outer case b; but it is preferably softened at its open end by being annealed, while the outer case may be drawn very hard to facilitate its extraction from the gun, this co1nbination of soft and hard metal adding consid- Serial No. 292,619. (No model.)

erably to the strength of the case. The base a of the inner case is of the ordinary form and is adapted to carry the ordinary priming at the center. It is stamped up of the form shown and gradually tapers off in thickness where it joins the sides a',which are rather thinner at the front end than the outer case b, the two a and I) being together only about equal in thickness to that of the ordinary case. The part a may be cylindrical externally and the part b cylindrical internally; but the part b is usually very slightly conical, while the part a is cylindrical and enters freely about half-way into I), and is then forced tightly therein, so as to virtually form one solid structure therewith. It is essential that the inner sheath a should extend at least as far as and abut against the shoulder b, so that it should be caused to adapt itself to the form of the shoulder of the outer case by being compressed or upset inwardly at the mouth, as shown in Fig. 1. This is effected by forcibly driving the inner case (which has previously been filled with the solid or compressed charge while it was in the straight form shown in Fig. 2) into the outer case while the latter is supported in a steel mold of corresponding form with a through aperture for the exit of the bullet in case of accidental discharge. The open end of the inner case, having been softened by annealing, as above mentioned, becomes cramped or upset inward on meeting the shoulders of the outer case when thus forcibly driven in by end pressure applied to its base.

Upon the discharge of the cartridge the cylindrical part a of this inner case tends to become expanded by the pressure of the gases, so as to make an absolutely gas-tight joint with the outer case I), particularly at the point where the inwardly-cramped mouth abuts, as above described, against the shoulder of the outer case.

The part a is provided with a coned flange d, which fits into a corresponding seat (1 in the end of b, which is flanged externally, as usual.

In order to protect the cartridge from moisture and prevent oxidation of the metal by the contact therewith of the explosive, it is preferable to wrap the charge in oiled paper hefore introducing it into the inner case a a, and to further exclude moisture the external surface of the part a may be varnished before introducing it into the case b.

It will be apparent that a cartridge constructed as above described will be safer and more serviceable in use, since there can be no danger to fear from flaws in the metal or other defects which are occasionally incidental to the manufacture of solid drawn cartridges. The cartridge is also safer, and therefore more serviceable, than cartridges charged at the base and having their base ends closed by mere plugs driven into them. This cartridge is also specially adapted for use in quick-firin g guns of larger calibers than are now being introduced.

I would have it understood that my invention is limited to bottle-shaped metallic cartridges which are charged with a solid or compressed charge wholly contained within an inner case, which is driven into the base end of the outer tube until its front end forcibly abuts against the shoulder of the said outer tube.

Having now particularly described and ascertained the nature of the said invention and in what manner the same is to be performed, I declare that what I claim is- 1. The herein-described metallic cartridge, consisting of the case I), having the shoulder Z) near the forward extremity, and the case a within the case b, upset inwardly at the front extremity at a in correspondence with the inner face of the shouldered portion of the case b, and having the closed base at its other extremity, substantially as shown and described.

2. The herein-described metallic cartridge, consisting of the case Z), having the shoulder b near one extremity and the seat d at its other extremity, and the case a within the case b upset inwardly at one extremity, at a in correspondence with the inner face of the shouldered portion of the case b, and having the base cl at its other extremity,substantially as shown and described.

The foregoing specification of my improvements in metallic cartridges signed by me this 7th day of November, 1888.

ABRAHAM MARTIN.

NVitnesses:

G. F. WVARREN, P. WooDwARD. 

